Apparatus and method for the electrolytic production of metal hydroxide



Dec. 27, 1966 P. s. ROLLER 3,294,665

APPARATUS AND METHOD FOR THE ELECTROLYTIC PRODUCTION OF METAL HYDROXIDEFIG.2.

72 INVENTOR Paul 8. Roller FiGA. Q m

Dec. 27, 1966 P. s. RCLLER 3,294,665

APPARATUS AND METHOD FOR THE ELECTROLYTIC I PRODUCTION OF METALHYDROXIDE Filed July 12, 1963 5 SheetsSheet 2 I- 24 4O 49 3 I FRG. 4.

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APPARATUS AND METHOD FOR THE ELECTROLYTIC PRODUCTIQN OF METAL HYDROXIDER\ ,90 INVENTOR Paul 8. Roller United States Patent 3,294,665 APPARATUSAND METHOD FOR THE ELECTRO- LYTIC PRODUCTION OF METAL HYDROXIDE Paul 5.Roller, 2325 42nd St., NW., Washington, D.C. 20007 Filed July 12, 1963,Ser. No. 294,677 19 Claims. (Cl. 204-227) The invention pertains toimprovements in the electrolytic production of insoluble metalhydroxides, and more particularly to that of aluminum or iron hydroxide.

Insoluble metal hydroxide can be formed chemically by precipitation, orelectrolytically from anodes of the metal in conducting water or aqueoussolution. Metals for the purpose include magnesium, zinc, copper,silver, iron and aluminum. At the present time, iron and aluminum arethe most important, because their trivalent hydroxides are coagulants,which are applicable to water purification on a wide scale.

In the case of iron anodes, ferrous hydroxide is initially formed, sothat oxygen is required, present or provided for, to convert it into thedesired trivalent hydroxide.

The electrolytically trivalent hydroxides with their included coagulatedimpurities may be directly filtered, or may be made to form a fioc whichis settled before filtration.

Cathodes to said anodes may be of any suitable material. Preferably, thesame metal is employed for both anode and cathode, in which instance theelectrodes receive reverse, electrolytic current.

According to applicants U.S. Patent 2,860,090, two metalhydroxide-producing electrodes are employed which are in mutual relationto one another, wherein one electrode is in electrolytic circuit, whilethe other is alternately out of electrolytic circuit and is beingdepolarized and readied for reverse current.

Heretofore, assemblages of electrodes have been employed in which theelectrode plates have been modified, as by hole drilling, and mutuallysecured to form a unitary structure. For water treatment purposesparticularly, it is desired on the contrary that the electrodes shall beeach readily accessible, structurally and electrically.

According to applicants U.S. Patents 3,006,826 and 2,919,235, a soft gelfilm is formed on the electrodes during electrolysis. If this film isantecedently removed, the formation of hard deposit or crust on theelectrodes is avoided.

One method of removing the film is by wiping of the electrodes. Thewiping has to be sufliciently rapid, intrinsically effective and extendover the entire exposed plate in order to obtain satisfactoryelectrolytic output. Portions of the electrode that are defectivelywiped become indurated, and may nucleate various ramifying growths.

Reciprocal linear wiping, as contrasted with rotary wiping, isintrinsically more effective in rejecting wiped matter. However, it haspresented more problems in view of a desired close spacing of theelectrode plates, their thinning down due to electrolytic consumption,and the demand of complete wiping to a confronting electrode edge.

In the present invention, the electrode plates are slidingly assembledin a plurality of co-planar groups. Wiper assemblies are demountablyinterposed between said groups, and the wipers thereof are passedreciprocatingly over the member electrode plates and insulating elementsof each said co-planar group. I

It is an object of the invention to provide for slidable installation orremoval of an individual electrode plate in a plurality thereof.

Another object is to provide for a co-planar formation "ice ofco-operative electrode plates all of which are served by but one wiper.

A further object is to provide for individual current leads to eachelectrode plate.

Still another object is to provide for shrouding of the current leadcontacts from the direct electrolytic current path.

A further object is to provide for maintenance of wiping pressure in thepresence of slack caused by thinning of the electrode plates.

A still further object is to provide for the practicable wiping of anelectrode plate to and beyond the confronting edge thereof.

Another object is to provide for re-flexing of a wiper strip into anacute angular posture on its reciprocating, return stroke.

Still another object is to provide for the skimming of accumulatedmatter from a Wiper-strip in the course of its normal movement.

A further object is to provide for the individual, detachableinstallation of a wiper assembly between adjacent coplanar electrodegroups, and its detachable re,

moval therefrom.

With these and other objects and advantages in mind, as will become moreapparent hereinafter, reference is made to the accompanying drawings, inwhich:

FIG. 1 is a vertical sectional view longitudinally through anelectrolytic apparatus according to the invention, showing one form of awiper assembly between adjacent electrode plates;

FIG. 2 is a sectional view taken on line 22 of FIG. 1;

FIG. 3 is a side view in elevation of an alternate wiper assembly;

' FIG. 4 is an enlarged fragmentary sectional view taken on line 4-4 ofFIG. 3;

FIG. 5 is a sectional view taken on line 5-5 of FIG. 1 and showing aco-planar group of electrode plates and associated insulating strips;

FIG. 6 is an enlarged fragmentary sectional view taken transverselythrough an alternate co-planar group, illustrating more particularlyforms of border, collateral and separator strips thereof;

FIG. 7 is an enlarged fragmentary sectional view of an alternate currentlead to an electrode plate;

FIG. 8 is a sectional view taken on line 8-8 of FIG. 1 and showing themovable carriage for a wiper reciprocating drive means;

FIG. 9 is an enlarged fragmentary section on line 9-9 of FIG. 8illustrating a detachable joint between a carriage and the end of alateral arm of a wiper assembly;

FIG. 10 is an enlarged fragmentary section taken on line 1010 of FIG. 8illustrating the U-shaped end of a slide-member of a carriage;

FIG. 11 is a view similar to FIG. 8 and showing an alternate carriage,and

FIG. 12 is an enlarged fragmentary section on line 12-12 of FIG. 11illustrating a detachable joint between said carriage and the alternateend of a lateral arm.

In describing the preferred embodiment of the invention illustrated inthe drawings, in which similar parts are numbered the same, specificterminology will be employed for the sake of clarity. However, theinvention is not to be considered limited to the specific termsselected; rather each specific term will be understood to include alltechnical equivalents operating in a similar manner to accomplish asimilar purpose.

Referring now in detail to the drawings, specifically to FIGS. 1 and 2,the invention comprises a receptacle or tank 10, suitably insulated,adapted to contain conducting water or aqueous liquid, and provided withconduits 11 and 12 on end walls 14, for transfer of liquid through saidreceptacle. Secured to the inner sides of lateral walls 13 of saidreceptacle by screws 17 and nuts 18 over water-tight insulating bushings19 are two oppositely disposed liners or slabs 21 of rigid insulatingmaterial and having in their confronting surfaces a plurality ofparallel grooves 22 which are mutually aligned and matching to slidinglyreceive the lateral ends of metal hydroxide-producing electrode plates24. In lieu of the liners 21, the lateral walls 13 may be formed ofinsulating material and be provided with the grooves 22. Said groovesextend from and open through the top edges 27 of slabs 21 part-waydownward to treads 28 which are spaced above the bottom edges 30 ofslabs 21, said treads 28 serving to support the plates 24, or thecoplanar groups hereinafter described.

Border strips 25 of insulation material are adjacent the transverseedges of said plates 24, and their lateral ends likewise are slidinglysituated in the grooves 22. They may be of the same thickness as saidplates, or

except for the ends in said grooves may be thinner than said plates.

An electrode plate 24 and associated top and bottom border strips 25comprise one form of a co-planar electrode group, the plurality of whichis equal to the plurality of. matching grooves 22 in slabs 21. Each saidco-planar group is secured in grooves 22 by an insulating bar 31 overthe top border strip 25. Bar 31, suitably fastened to slab 21 or wall13, is of the same width as said slab and is provided with cut-outs 34in order to clear said channels 29.

Collateral strips 32 are preferably included in a coplanar group and areadjacent to and interior of border strips 25, as shown in FIG. 6.Generally of insulating material, they may be part of, or separate, fromsaid border strips. They are at all times thicker than said borderstrips, and protrude over them.

A co-planar electrode group in its more general form comprises two metalhydroxide-producing electrode plates 24 and 24', auxiliary electrodeplates 35 neighboring said plates 24 and 24', an oxidant-producingelectrode plate 37, insulating separator strips 38 between adjacentelectrode plates, collateral strips 32, and border strips 25 at top andbottom. Said separator and collateral strips may be contiguous to anelectrode plate adjacent thereto, or may be displaced therefrom andinclude a gap therebetween. suitable material, may be of the samethickness as the adjacent electrode plates, or alternatively, except forthe ends in grooves 22, may be thicker than said adjacent plates andprotrude over them. as shown in FIG. 6.

Metal hydroxide-producing plates 24 and 24' comprise a supplementarypair in accordance with my US. Patent 2,860,090, while auxiliary plates37 function co-operatively with said metal hydroxide-producing plates inaccordance with my co-pending patent application, Serial No. 177,082,now U.S. Patent No. 3,256,162. Oxidantproducing electrode plates 37 areemployed to generate oxygen or chlorine, the oxygen for example in theinstance of iron electrodes in the co-planar group, and the chlorine fordisinfection. The chlorine is generated in the presence of dissolvedsodium chloride in the water. It will be clear that still other kinds ofelectrode plates may be included in the aforesaid co-planar group forany special purpose as desired.

A plurality of similar bus bars 40 and 40', FIGS. 2 and 5, are situatedon opposite sides of receptacle 10 exterior to lateral walls 13, and areinsulatingly attached to said receptacle, for example by insulatingbrackets 41 on walls 14. A pair of bus bars 40 and 40' are provided foreach said kind of electrode plate, and are positioned mid-way of thelateral ends of the plurality thereof.

Electrolytic power source 43, which may be an omnibus supply for allsaid kinds of electrodes, contains provisions for current reversal,switches, and resistances, and may include one or more rectifiers, asrequired. It is con- Separator strips 38, of plastic or other nected toeach bus bar 40 by lead 44 and to each bus bar 40' by lead 44'.

Current lead screws 46, issuing from each said bus bar through threadedholes 47 therein, make screw-tight contact with the edges of the saidelectrode plates in grooves 22. Each said lead screw 46 is insulatedfrom receptacle 10 by liquid-tight fitting 48, which is secured inlateral wall 13 by a nut 49 on said screw.

As shown more particularly in FIG. 7, liquid-tight fitting 48 maysuitably comprise an O-ring 50 secured in position by a bushing 51 thatis thrusted upon by nut 49 on the current lead screw 46. Current leadscrews 46 on bus bar 40 make contact with every other of the electrodeplates associated with said bus bar, while said lead screws on bus bar40 make contact with the alternate of said plates.

An alternate current lead is shown in FIG. 7 and includes a resilientmember or spring 54 pressing against the lateral end of an aforesaidelectrode plate, such as electrode plate 24 in groove 22, and held insaid groove by a screw 53. This screw may be sealed by the liquid tightfitting 48 as previously described, said nut 49 being mounted thereon.The screws 53 may be attached to bus bar 40 or 40' by nuts 56.

A wiper assembly interposed between said co-planar groups of electrodeplates and insulating strips, comprises two rubber elements or strips 58extending transversely across said group, two similarly extendingholders 59 respectively therefor, a plurality of resilient supports 60for each said holder and urging the wiper strip thereof to therespective co-planar group, and support means for said resilientsupports. The foregoing assemblies are shown diagrammatically in FIG. 1wherein the resilient supports 60 are mounted back-to-back on supportmeans comprising a single cross-beam 61. Preferably, however, as bestshown in FIGS. 3 and 4, the support means comprises an upper cross-beam66 and a lower cross-beam 67 and the resilient supports 60 for one wiperassembly is mounted on beam 66 while the supports 60 for the other wiperassembly is mounted on beam 67. Wipers 58 now appertain both to uppercross-beam 66 and lower cross-beam 67, whereby each said wiper withholder 59 therefor lies in a plane separate from the other and occupiesthe entire space between said co-planar groups.

As best shown in FIG. 4, a wiper strip 58 is held securely in U-shapedholder 59, or may be movably held therein. Each of said plurality of theresilient supports 60 is attached to the respective holder 59 by a screw62, which passes through holes or oversize slots in rubber strip 58. Theresilient supports 60 may be constituted by flat springs as indicated inFIG. 1, but it is preferred that these supports comprise a springportion 63 and a rigid arm portion 64 secured together by a fastener 65.59 and the spring 63 can be fixed to the respective crossbeam 61, 66 or67 by a screw 69.\ In addition to the cross-beams, the support means forresilient supports 60 comprises vertically disposed lateral arms 68attached to said beams and movable in matching channels 29, and acarriage or frame 70 supporting all said arms 68 for verticalreciprocation.

Reciprocating drive means 72 for said wiper assembly may comprise one ormore fluid operated cylinders and appurtenances, and includes a drive orpiston rod 73 passing in liquid-tight connection into receptacle 10through bottom 71 thereof. The carriage 70 may comprise a rectangleframework including two lateral members 75 proximal to lateral walls 13,two end-members 76 proximal to end-walls 14, and a center-member 78. Aboss 77 on said center-member 78 receives drive rod 73, for example in athreaded fit. Appendages or tongues 80 on each of the four corners ofsaid framework are movable in guide channels 81 on end-walls 14. Thereciprocating movement of the carriage 70 imparted by The rigid arm canbe attached to the holder drive rod 73, is stabilized by said appendagesconstrained in channels 81.

The lateral members 75 comprise elongate bars the upper surfaces ofwhich, as best shown in FIG. 9, are channelled to provide upstandingflanges 83 and 84 with a platform 85 therebetween and contiguous withinner flange 84. A groove or base 86 is provided within the channelledupper surface of each bar 75 and below the platform 85, such groovebeing contiguous with the inner side of the outer flange 83. The flanges83 and 84 constitute outer and inner stops for a slide-member 87 thatreposes on platform 85 and is provided with U-shaped ends 89 that doubleunder the ends of the bar 75 as shown in FIG. 10. When adjacent to outerstop 83, said slidemember may be secured in this position by a pin 90passing through aligned holes 88, 88 in U-sha-ped end 89 and platform85.

Lateral arms 68 are adapted to be detachably engaged in the lateralmembers 75 of carriage 70. For this purpose, each arm 68 is providedwith an L-shaped lower end forming a foot 92 which rests in groove 86inwardly of outer stop 83. Said foot is retained during wiping byslide-member 87 moved over it, said slide-member being secured asaforesaid by pin 90. All lateral arms 68 of the plurality of wiperassemblies are in this wise retained by the two slide-members 87 ofcarriage 70.

A wiper assembly may be installed between co-planar groups of electrodeplates and insulating strips by pushing and pins 90 are dropped intoplace.

In detachably removing said wiper assembly from between adjacent groupsof electrode plates and insulating strips, pins 90 are first lifted outof the aforesaid aligned holes and slide-members 87 are moved towardinner stop 84 to uncover feet 92. Thereupon, by pulling upward on uppercross-beam 66, or alternately lower cross-beam 61, said wiper assemblyis withdrawn from between said groups.

Alternately, lateral arms 68' each may be provided with a tapered end 94above which are situated opposite indents 95 as shown in FIGS. 11 and12. In this arrangement, the lateral members 75' of carriage 70' areprovided with a plurality of blocks 100 mounted on their upper surfaces,each block 100 being aligned with a lateral arm 68. Blocks 100 arenotched to conform with taper-end 94, and are provided at their sides101 with hook springs 102 extending above said blocks. Lateral arm 68 isheld in block 100 in virtue of springs 102 being engaged in indents 95.The tension of said springs is sufficiently high for the engagement towithstand the pull of wiping.

A wiper assembly is installed by pushing downward on upper cross-beam66, or alternately cross-beam 61, whereby taper-ends 94 are entered intoblocks 100 obversely to springs 102, which thereupon snap into indents95. The removal of said wiper assembly is effected by pulling upward onupper cross-beam 66, whereby taper-ends 94 are withdrawn from blocks 100against the holding tension of springs 102.

During electrolytic metal hydroxide-production, the plurality of wiperassemblies is moved reciprocally by drive means 72 transmitting power tocarriage 70 or 70' and its lateral members 75 or 75, anns 68 andcrossbeams 66 and 67, or alternately cross-beam 61. Wiper strips 58connected to said cross-beams are thereby passed over each co-planargroup of electrode plates and insulating strips, coming to rest at theend of each reciprocating stroke on a border strip 25.

The advantages of the electrolytic apparatus as hereinabove describedare numerous, and provide new and improved marks of performance.

Instead of burdensome pre-assemblies separately of electrode plates 24,24 or 37, these are individually installable by a sliding fit in grooves22. Electrolytic residues of said plates 24 or 24' are easily removed bypushing them out with slidable separator strips 38 as tools.

The provision for each electnode plate 35 being close to an electrodeplate 24 or 24' in a co-planar group has processing advantagesinaccordance with my co-pending patent application, Serial Number 177,082,now US. Patent No. 3,256,162.

Wiper assemblies between adjacent co-planar groups are individually anddetachably installable and removable, resulting is simplified apparatusassembly and maintenance.

Two wipers 58 and holders 59 are required between adjacent co-planargroups of electrode plates and insulating strips. According to thepreferred construction as hereinabove described, no greater spacebetween coplanar groups is necessary than that which will accommodatebut one said wiper and holder therefor. As a result, close spacing ofsaid co-planar groups of electrode plates is desirably achieved.

Flat springs 60 when elongated result in substantially constant wipingtension against increasing slack caused by the electrolytic thinningdown of electrode plates 24 and 24'. Arms 64 provide a rigid springsubstitute, whereby excessively long springs, and buckling thereof, areavoided.

The employment of electrode plates 24, 24', 35 and 37 in a co-planargroup permits of but one wiper being required for all said plates,instead of a separate wiper for each of said plates when the assembliesthereof are independent.

Moreover, with such a co-planar group all water flowthrough receptacle10 receives an aliquot of electrolytic metal hydroxide, alternately fromelectrode plates 24 or 24'. When said plates are, however, in separategroups or assemblies, that fraction of water flowing past thenonfunctioning alternate plates 24 or 24' disadvantageously receives nometal hydroxide.

A still further benefit of the co-planar group is that oxygen generationfrom an electrode 37 takes place desirably close to an acceptor ironelectrode 24 or 24.

Each of the electrode plates in a co-planar group is independentlyprovided with an electrode lead contact. Any particular contact may beeasily broken by backing away screw 46, or disengaging alternate screw53 from bus bar 40 or 40'. Each said electrode contact is,-moreover,protected from the corrosive effect of the electrolytic current by beingshrouded in groove 22. The employment of border strips 25 permits wipers58 to pass thereto beyond the edge of an adjacent electrode plate 24 or24', whereby said plates are completely wiped, including the edgethereof. Moreover, the length of wiping stroke does not have to becritically adjusted, in view of the indifferent positioning of wiper 58on said border strips.

Wiper strips 58 are bent acutely toward the surface being wiped. Withthis inclination, the edges of said wipers do not snag in theinterstices between said electrode plates and adjacent separator stripsor collateral strips. Such acute presentation is therefore necessary atall times. Accordingly, after completing a particular stroke, wiperstrips 58 must re-flex into the required acute position for the returnstroke. The re-flexing is assured by the construction as aforesaid.Having come to rest on border strip 25,'wiper strip 58 is flipped andautomatically re-flexed by collateral strip 32 protruding over saidborder strip. This effect is augmented by said border strip beingrelatively thin, that is thinner than an electrode plate, as set forthhereinabove.

Collateral strip 32 and separator strip 38 are each desirably thickerthan an electrode plate adjacent thereto, whereby they present anoverhanging edge to an advancing wiper strip 58. Such edge serves toskim accumulated matter from said wiper strip, and keep it clean. A gap,as aforesaid, between an electrode plate and said col lateral orseparator strip avoids that sharp corner between them when they arecontiguous. An accumulation of wiped matter which may occur in such acorner is thereby avoided.

It is to be understood that the form of the invention herewith shown anddescribed is a preferred embodiment. Various changes may be made inshape, size and arrangement of parts without departing from the scopeand spirit of the invention as claimed.

Having thus described my invention, I claim:

1. An apparatus for the electrolytic production of insoluble metalhydroxide in aqueous solution, comprising a receptacle, the oppositelateral walls of said receptacle being provided with matching parallelgrooves, a plurality of co-planar electrode groups, each groupcomprising metal hydroxide-producing electrode plates and insulatingborder strips mounted group by group in said grooves with their lateralends slidingly disposed therein, means to retain each said group in saidgrooves, current supply means for said plates, and wiping means toremove a soft gel film from said plates during electrolysis.

2. An apparatus for the electrolytic production of insoluble metalhydroxide in aqueous solution comprising a receptacle, the oppositelateral walls of said receptacle being provided with matching parallelgrooves, a plurality of co-planar electrode groups, each groupcomprising metal hydroxide-producing electrode plates, insulatingseparator strips therebetween and insulating border strips mounted groupby group in said grooves with their lateral ends slidingly disposedtherein, means to retain each said group in said grooves, current supplymeans contacting said plates on their ends within said grooves, andwiping means to remove a soft gel film from said plates duringelectrolysis.

3. An apparatus for the electrolytic production of insoluble metalhydroxide in aqueous solution comprising a receptacle, the oppositelateral walls of said receptacle being provided with matching parallelgrooves, a plurality of co-planar electrode groups each group comprisingmetal hydroxide-producing electrode plates, insulating separator stripstherebetween, insulating border strips, collateral strips adjacent toand interior of said border strips, said collateral strips being thickerthan said border strips and protruding thereover, said plates and stripsmounted group by group in said grooves with their lateral ends slidinglydisposed therein, means to retain each said group in said grooves,current supply means contacting said plates on their ends within saidgrooves, and wiping means to remove a soft gel film from said platesduring electrolysis.

4. An apparatus for the electrolytic production of insoluble metalhydroxide in aqueous solution comprising a receptacle, the oppositelateral walls of said receptacle being provided with matching parallelgrooves, a plurality of co-planar electrode groups each group comprisingmetal hydroxide-producing electrode plates, electrode plates auxiliarythereto, insulating separator strips therebetween and insulating borderstrips mounted group by group in said grooves with their lateral endsslidingly disposed therein, means to retain each said group in saidgrooves, current supply means contacting said plates on their endswithin said grooves, and wiping means to remove a soft gel film fromsaid plates during electrolysis.

5. An apparatus for the electrolytic production of insoluble metalhydroxide in aqueous solution comprising a receptacle, the oppositelateral walls of said receptacle being provided with matching parallelgrooves, a plurality of co-planar electrode groups each group comprisingmetal hydroxide-producing electrode plates, electrode plates auxiliarythereto, oxidant-producing electrode plates, insulating separator stripsbetween adjacent electrode plates and insulating border strips mountedgroup by group in said grooves with their lateral ends slidinglydisposed therein, means to retain each said group in said grooves,current supply means contacting said plates on their ends within saidgrooves, and wiping means to remove a soft gel film from said platesduring electrolysis.

6. An apparatus for the electrolytic production of insoluble metalhydroxide in aqueous solution comprising a receptacle, the oppositelateral walls of said receptacle being provided with matching parallelgrooves, metal hydroxide-producing electrode plates mounted in saidgrooves with their lateral ends slidingly disposed therein, means toretain said plates in said grooves, current supply means contacting saidplates on their ends within said grooves, and wiping means to remove asoft gel film from said plates during electrolysis.

7. Claim 2 wherein said separator strips are thicker than the adjacentsaid electrode plates.

8. Claim 3 wherein said border strips are thinner than said electrodeplates.

9. Claim 3 wherein said collateral strips are thicker than saidelectrode plates.

10. Claim ll wherein said current supply means comprises screwscontacting said plates at their lateral ends in said grooves.

11. Claim 1 wherein said current supply means comprises resilientmembers mounted in said grooves and contacting said plates at theirlateral ends therein.

12. An apparatus for the electrolytic production of insoluble metalhydroxide in aqueous solution, comprising a receptacle, the oppositelateral walls of said receptacle being provided with matching parallelgrooves, a plurality of co-planar electrode groups each group comprisingmetal hydroxide-producing electrode plates and insulating border stripsmounted group by group in said grooves with their lateral ends slidinglydisposed therein, means to retain each said group in said grooves,current supply means for said plates, wiper strips on each said plate toremove a soft gel film from the surfaces thereof, holders for said wiperstrips, resilient supports on said holders directing said wipers to therespective wiped plates, and drive means connected to said resilientsupports to move said wipers reciprocatingly across said plates.

13. An apparatus for the electrolytic production of insoluble metalhydroxide in aqueous solution, comprising a receptacle, the oppositelateral walls of said receptacle being provided with matching parallelgrooves, a plurality of co-planar electrode groups each group comprisingmetal hydroxide-producing electrode plates and insulating border stripsmounted group by group in said grooves with their lateral ends slidinglydisposed therein, means to retain each said group in said grooves,current supply means for said plates, wiper strips on each said plate toremove a soft gel film from the surfaces thereof, holders for said wiperstrips,'rigid arms connected to said holders, fiat spring means attachedto said arms directing said wipers to the respective wiped plates, anddrive means connected to said spring means to move said wipersreciprocatingly across said plates.

14. An apparatus for the electrolytic production of insoluble metalhydroxide in aqueous solution comprising a receptacle, the oppositelateral'walls of said receptacle being provided with matching parallelgrooves and matching parallel channels intermediate said grooves, aplurality of co-planar electrode groups each group comprising metalhydroxide-producing electrode plates and insulating border stripsmounted group by group in said grooves with their lateral ends slidinglydisposed therein, means to retain each said group in said grooves,current supply means for said plates, two wiper strips between oppositesaid co-planar groups to remove a soft gel film from the respectivesurfaces thereof, two holders respectively for said wiper strips, flatspring means on said holders directing said wipers to the respectivewiped plates, a frame comprising cross-beam means supporting said springmeans and lateral arms at the ends of said cross-beam means slidinglymovable in said channels, a carriage in said receptacle, the ends ofsaid lateral arms detachably engaged with said carriage, andreciprocating drive means connected to said carriage.

15. Claim 14 wherein the ends of saidlateral arms are L-shaped and saidframework includes a base supporting said L-shaped ends and aslide-member over said base retaining said L-shaped ends.

16. Claim 14 wherein said lateral arms have a taperend with indentsthereover, and said framework includes notched blocks and hook springson the sides thereof, said taper-ends being retained in said blocks bysaid springs secured in said indents.

17. Claim 14 wherein said carriage is provided with a plurality ofappendages, and guide-members are mounted on the walls of saidreceptacle, said appendages being movable in said guide-members.

18. Claim 14 wherein said cross-beam means comprise an upper cross-beamand a lower cross-beam, and said spring means on one said holder isattached to said lower cross-beam and on the other said holder to saidupper cross-beam.

10 19. In the electrolytic production of metal hydroxide from electrodeplates bordered by insulating strips, passing wipers over the electrodeplates beyond the confronting edge thereof to said insulating strips,coming to rest thereon, and then passing the wipers over said plates0ppositely and reciprocatingly.

References Cited by the Examiner UNITED STATES PATENTS 3,006,826 10/1961Roller 204-96 3,182,010 5/1965 Roller 204-227 FOREIGN PATENTS 650,27410/1962 Canada.

JOHN H. MACK, Primary Examiner.

W. VAN SISE, Assistant Examiner.

6. AN APPARATUS FOR THE ELECTROLYTIC PRODUCTION OF INSOLUBLE METALHYDROXIDE IN AQUEOUS SOLUTION COMPRISING A RECEPTACLE, THE OPPOSITELATERAL WALLS OF SAID RECEPTACLE BEING PROVIDED WITH MATCHING PARALLELGROOVES, METAL HYDROXIDE-PRODUCING ELECTRODES PLATES MOUNTED IN SAIDGROOVES WITH THEIR LATERAL ENDS SLIDINGLY DISPOSED THEREIN, MEANS TORETAIN SAID PLATES IN SAID GROOVES, CURRENT SUPPLY MEANS CONTACTING SAIDPLATES ON THEIR ENDS WITHIN SAID GROOVES, AND WIPING MEANS TO REMOVE ASOFT GEL FILM FROM SAID PLATES DURING ELECTROLYSIS.